Thermal reforming of a catalytic reformate



Jul 28, 1959 W. N. N. KNIGHT THERMAL REFORMING OF A CATALYTIC REFORMATE Filed Nov. 15,- 1956 DEBUTANIZED RERUN LIGHT THERMAL j REFORM/ATE THERMAL- REFORMER 6 NAPHTHA CATALYTIC DEBUTANIZED ols-nLLA'non TOTAL FEED REFORMER GASOLINE 'GAsouNE HEAVY GASOLINE 6 THERMAL REFORMER DEBUTANIZED RERUNHEAVY THERMAL REFORMATE INVENTOR WARREN NEVIN NORTON KNIGHT ATTORNEYS United States Patent 2,897,132 THERMAL REFORMING OF A CATALYTIC REFORMATE Warren Nevin Norton Knight, Sunbury-on-Thames, England, assignor to'The BritishPetroleum Company Limited, London, England, a British joint-stock corporation Application November 15, 1956, Serial No. 622,337 Claims priority, application Great Britain November 24, 1955 3 Claims. (Cl. 208-65) This invention relates to motor fuels for the operation of internal combustion engines.

Hydroforming is a well-known process for producing high octane motor gasolines from low octane petroleum naphthas. In the hydroforming process, the low octane petroleum naphtha is contacted at elevated temperature in the presence of hydrogen with a catalyst capable of converting naphthenes into aromatics to give a product of greatly increased octane number. A hydroforming process that has been widely adopted uses a platinumcontaining catalyst and such a process will hereinafter be referred to as Platforming. The catalytic reformate of such a process will hereinafter be referred to as Platformate. It has long been known that the octane number of a catalytic reformate can be increased by thermal reforming, and it has recently been proposed to apply this principle to the product of the Platforming process.

It has now been discovered that there are advantages in subjecting portions of the total catalytic reformate to thermal reforming separately.

According to the invention, a catalytic reformate is separated into a high boiling fraction and a low boiling fraction, the two fractions are subjected to thermal reforming separately, the low boiling fraction being reformed at a greater severity than the high boiling fraction, and the products of the thermal reforming operations are blended to produce a high octane gasoline.

The cut point between the low boiling and high boiling fractions of the catalytic reformate should preferably lie within the range 110 to 150 C.

The thermal reforming operations are preferably carried out at temperatures within the range 1,000 to 1,200 F. and at a pressure within the range 200 to 1,200 p.s.i.g., and the conditions in the two operations are preferably such that conversion to C and lighter on the low boiling fraction is in the range 20% to 35% wt. and on the high boiling fraction 5% to 20% wt.

The process according to the invention has the advantage that it is possible to subject the low boiling fraction to the severe reforming conditions necessary to produce "ice under the following conditions:

Pressur 500 p.s.i.g. Catalyst inlet temperature 920 F. Gas recycle rate 9200 s.c.f./ b. Space velocity 2.0 v./ v'./ hr.

A Platformate of 82 octane number (Research) was obtained and was distilled in a 10 plate continuous column to give a light Platformate of 130 C. ASTM end point (60% Wt.) and the corresponding residue (40% wt.).

The light Platformate (75 octane number) was reformed at 750 p.s.i.g. and at 1,060 F. to give the following product distribution:

Percent wt. C and lighter 26 C 17 Gasoline 50 Polymer 7 The gasoline (30% wt. on total Platformate) had an octane number of 97 research. The heavy Platformate (94 octane number) was reformed at 750 p.s.i.g. and 1,030 F. to give the following product distribution? Percent wt.

C and lighter 7 Gasoline 87.8 Polymer 2.2

the maximum upgrading, whereas these conditions cannot Percent wt. Platinum 0.37 Fluorine 0.51 Chlorine 0.26 Alumina 98.8

The gasoline (35% wt. on total Platformate) had an octane number of iso-octane-f-0.8 m1. TEL/USG octane number (Research).

The blending of these two thermally reformed gasolines gave a yield of 65% wt. on total Platformate of a gasoline of iso-octane+0.30 ml. TEL/USG octane number (Research). If the total Platformate were reformed, the maximum octane number obtainable without excessive coking of the unit would be iso-octane+0.05 ml. TEL/USG.

The invention is illustrated diagrammatically in the accompanying flow-sheet.

Naphtha is fed through line 1 to a catalytic reformer 2 and reformed debutanized gasoline passes via line 3 to the middle of a distillation column 4, which separates the gasoline into two fractions with a cut point in the region of -150 C. The light gasoline taken off overhead through line 5 has a relatively low octane number and is thermally reformed in reformer 6 at a relatively high severity. The heavy gasoline withdrawn from the column 4 through line 7 is thermally reformed in reformer 8 at a lower severity, since it has initially a relatively high octane number. The products from both thermal reformers are re-run and debutanized and pass via lines 9 and 10 respectively to a common line 11 for blending and storage.

Iclaim:

l. A process for producing gasoline of increased octane number from a liquid catalytic reformate, which reformate is a product of a hydroforming process in which is used a platinum-containing catalyst, comprising separating the catalytic reformate into a high boiling liquid fraction and a low boiling liquid fraction, thermally reforming two fractions separately, each at a temperature within the range l000 to 1200 F. and a pressure within the range 200 to 1200 p.s.i.g., but at different severities, the low boiling fraction being reformed at the greater severity, and blending the products of the thermal reforming operations.

2. A process as claimed in claim '1 wherein the cut point between the low boiling and high boiling fractions of the catalytic reformate lies within the range 110 to 150 C.

3. A process as claimed in claim 1 wherein the low boiling fraction is thermally reformed to give a conversion to C and lighter hydrocarbons in the range 20% to 35% and the high boiling fraction is thermally reformed to give a conversion to C and lighter hydrocarbons in the range 5% to 20%.

References Cited in the file of this patent UNITED STATES PATENTS Diwoky July 15, 1941 Welty Dec. 6, 1949 Haensel et a1 Nov. 17, 1953 Haensel et al. Apr. 3, 1956 Haensel et a1 Dec. 11, 1956 FOREIGN PATENTS Australia July 18, 1955 UNITED STATES PATENT OFFICE CERTIFICATION OF GORECTION Patent Nora 2,897,132 July 28, 1959 Warren Nevin Norton Knight It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 67 after "reforming" insert the e Signed and sealed this 6th day of June 1961.,

(SEAL) Attest:

DAVID L. LADD Commissioner of Patents ERNEST W. SWIDER Attesting Officer 

1. A PROCESS FOR PRODUCING GASOLINE OF INCREASED OCTANE NUMBER FROM A LIQUID CATALYTIC REFORMATE, WHICH REFORMATE IS A PRODUCT OF A HYDROFORMING PROCESS WHICH IS USED A PLATINUM-CONTAINING CATALYST, COMPRISING SEPARATING THE CATALYTIC REFORMATE INTO A HIGH BOILING LIQUID FRACTION AND A LOW BOILING LIQUID FRACTION, THERMALLY REFORMING TWO FRACTIONS SEPARATELY, EACH AT A TEMPERATURE WITHIN THE RANGE 1000* TO 1200*F. AND A PRESSURE WITHIN THE RANGE 200 TO 1200 P.S.I.G., BUT AT DIFFERENT SEVERITIES, THE LOW BOILING FRACTION BEING REFORMED AT THE GREATER SEVERITY, AND BLENDING THE PRODUCTS OF THE THERMAL REFORMING OPERATIONS. 